Approach on Component Selection for Ageing-Trend Analysis Within PSA Models

2009 ◽  
Author(s):  
Shahen Poghosyan ◽  
Armen Amirjanyan ◽  
Albert Malkhasyan
Keyword(s):  
Trend Analysis ◽  
Significant Contribution ◽  
Reactor Core ◽  
Component Selection ◽  
Core Damage ◽  
Ageing Effects ◽  
Level 1 ◽  
Selection For ◽  
Definition Of ◽  
Actual Configuration

The major advantage of PSA is the possibility of in-depth qualitative and quantitative analysis of NPP actual configuration with definition of factors introducing a significant contribution to the general risk of reactor core damage. However main lack of the PSA current models is neglect of equipment ageing effects. Neglecting of ageing effects in PSA could lead to incorrectness of risk profile and influent on risk-informed decision making process. To solve this issue incorporation of ageing aspects into PSA models for Armenian NPP Unit 2 was initiated. Implementation of ageing trend analysis for all PSA components is insuperable effort, so the first step of the analysis is component selection activity. This paper is addressing the approach on component selection for ageing-trend analysis within PSA models. Presented approach is based on ageing effect and risk importance data. The procedure was developed and implemented in the framework of ageing aspects incorporation into PSA level 1 model for Armenian NPP Unit 2.

PATIENT CARE AND STUDENT LEARNING IN A PEDIATRIC CLINIC

PEDIATRICS ◽  
1972 ◽  
Vol 50 (6) ◽  
pp. 847-848
Author(s):  
Robert J. Haggerty
Keyword(s):  
Patient Care ◽  
Student Teaching ◽  
Effective Management ◽  
Patient Dissatisfaction ◽  
Complex Problems ◽  
Teaching Objectives ◽  
Recruitment Procedure ◽  
Outpatient Departments ◽  
Selection For ◽  
Definition Of

Every pediatrician who has taught or worked in university pediatric outpatient departments recognizes the syndrome presented by Duff et al. in this issue of Pediatrics. The diagnosis is clear: effective student teaching is not occurring. The etiology of this problem is complex and not so clear. Some of the causes are inappropriate patient selection for beginning students, lack of effective administrative organization to achieve even limited teaching objectives, and lack of appropriate techniques to diagnose and manage the complex sociomedical problems presented. As a result, student, faculty, and patient dissatisfaction is very high. Effective management of the syndrome is even less clear. As with most complex problems, a clearer definition of the goals is the first step to a solution. What do we want the student to learn? How to gather information from families with such complex social and medical difficulties? Skills in diagnosis and management of common or rare health problems? Change of attitudes? Until each ambulatory program defines its teaching objectives more clearly in behaviorally measurable terms, effective management of the disease "poor patient care and teaching" will continue to elude us. I would, however, suggest the following considerations: 1. The first direct patient experiences which students have in ambulatory settings should be with patients who present considerably less complex problems than those available in most of our outpatient departments, and there should be a wider social class selection for the student's initial experience. To achieve this will require either a different patient recruitment procedure or the use of different settings for such education.

An Archaeological Approach to the Study of Cultural Stability

1955 ◽  
Vol 11 ◽  
pp. 32-57 ◽  
Author(s):  
Emil W. Haury ◽  
Robert L. Rands ◽  
Albert C. Spaulding ◽  
Walter W. Taylor ◽  
Raymond H. Thompson ◽  
...  
Keyword(s):  
Stability Problem ◽  
Significant Contribution ◽  
Time Perspective ◽  
Problem Area ◽  
Cultural Development ◽  
Instability Problem ◽  
Long Span ◽  
The Stability ◽  
Definition Of

The study of cultural stability requires a knowledge of cultural development over a reasonably long span of time. The definition of this time perspective is one of the major contributions of archaeology to the study of culture. The archaeologist therefore should be in a position to make a significant contribution to the appraisal of the stability problem itself. However, the lack of a commonly accepted anthropological definition of the concept of cultural stability imposes semantic difficulties which hinder the determination of practical limits for the stability- instability problem area. Moreover, the nature of the data available to the archaeologist conditions the kind of contribution he can make.

Development of Safety-Enhanced Fast Reactor by Using Minor Actinide Bearing Internal Blanket

2020 ◽  
Author(s):  
Sho Fuchita ◽  
Satoshi Takeda ◽  
Koji Fujimura ◽  
Toshikazu Takeda ◽  
Kazuhiro Fujimata
Keyword(s):  
Fast Reactor ◽  
Inner Core ◽  
Reactor Core ◽  
Minor Actinide ◽  
Core Damage ◽  
Burnable Absorber ◽  
Sensitivity Studies ◽  
Core Height ◽  
Gas Expansion ◽  
Control Rods

Abstract For a 750MWe sodium-cooled fast reactor core using MOX fuel, safety-enhancement measures have been studied to reduce the risk of core damage under unprotected loss of flow (ULOF) and unprotected transient overpower (UTOP) accidents. As passive measures the followings are considered: 1) adoption of the axial heterogeneous core configuration with sodium plenum and Gas Expansion Modules (GEMs) to lower sodium void reactivity for ULOF, and 2) addition of minor actinides (MAs) as burnable absorber and fertile nuclides to the internal blanket in the inner core to reduce burnup reactivity for UTOP. In this study, configurations of the safety-enhanced core were optimized based on sensitivity studies as follows. Firstly, effects of 1) above on the sodium void reactivity were evaluated by changing the inner core height, B-10 content of the upper shield, GEMs, and standby position of the backup control rods, which are the dominant factors of core behavior in the event of ULOF. Secondly, the effects of 2) above on the burnup reactivity were evaluated by changing the MA content in the internal blanket and the burnup period, which are the dominant factors of UTOP. Finally, by utilizing sensitivity analysis results, the safety-enhanced core which satisfies the provisional design goals has been developed. This core has negative sodium void reactivity and burnup reactivity less than 1 $.

RELAP5 Core Modeling Study for Level 1 PRA Thermal-Hydraulic Analyses

2013 ◽  
Author(s):  
Changjiang Yang
Keyword(s):  
Single Channel ◽  
Cross Flow ◽  
Operation Time ◽  
Medium Size ◽  
Damage Scenario ◽  
The Core ◽  
Core Damage ◽  
Level 1 ◽  
Flow Effects ◽  
Accident Scenarios

Thermal-hydraulic (T/H) analyses are used to support the level 1 Probabilistic Risk Assessment (PRA) success criteria and the manual operation time. To address the multiple-failure accident scenarios that are considered in the PRA, usually numerous T/H analyses were performed. So it is meaningful to develop a relative simple T/H model with acceptable accuracy for level 1 PRA T/H analyses. To achieve this object, the core modeling effects on the core damage progression were studied according to ASME/ANS RA-Sa-2009. Two types of core modeling methods were studied, including single channel core modeling and multi-channel core modeling. For the single channel core modeling, the study was focused on the axial nodes number effect. For the multi-channel core modeling, the cross-flow effects were studied. Several cases were calculated on a 3-loop PWR medium size break LOCA core damage scenario with Relap5/MOD3.2. Some key parameters related to the core state, such as peak cladding temperature (PCT), core water level and coolant inventory, were compared and analyzed. A kind of core modeling for level 1 PRA T/H analyses was suggested at the end.

scholarly journals Systematic component selection for gene-network refinement

2006 ◽  
Vol 22 (21) ◽  
pp. 2674-2680 ◽  
Author(s):  
N. Radde ◽  
J. Gebert ◽  
C. V. Forst
Keyword(s):  
Gene Network ◽  
Component Selection ◽  
Systematic Component ◽  
Selection For
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